Book on mobile computing?

can u suggest a book for mobile computing :
with gsm; gprs etc.
for engineerign. could u also also suggest some sites where i can find matter on electronics engineerig?? notes, docs and the rest??
I tried ocw[mit] but cant make much use of it,

Mobile Computing whose authors are Yavagal Asoke,Talukder and Roopa contains all the topics of mobile computing including GPS,GPRS,etc. Its publisher is Tata McGraw-Hill,one of the best publisher. You can also refer Mobile Computing-A Book of Reading whose author is C S R Prabhu.